The diverse functional roles of over 6,000 species of extant mammals that range in body size across eight orders of magnitude, from blue whales (Balaenoptera musculus) to tiny Etruscan shrews (Suncus ...etruscus), contribute to shaping Earth's ecosystems. Large mammalian herbivores (e.g., African elephants Loxodonta africana, American bison Bison bison, hippopotamuses Hippopotamus amphibius) and carnivores (e.g., wolves Canis lupus, pumas Puma concolor, sea otters Enhydra lutris) often have significant effects on primary producers in terrestrial, aquatic, and marine systems through nutrient cycling, energy flow, and the exertion of bottom-up and top-down processes. Small mammals, like bats, are important pollinators, dispersers of fruits, and consumers of arthropods, and others, especially rodents and primates, are important predators and dispersers of seeds. Many of these mammal-mediated processes occur simultaneously in the same ecosystem, and have significant effects on community structure of primary producers that in turn alter communities of other vertebrates and invertebrates. Many mammals also are ecosystem engineers (e.g., elephants, American beavers Castor canadensis, porcupines Erithezon dorsatum, prairie dogs Cynomys spp.) that create, significantly modify, or destroy habitat, and by doing so, they alter ecosystem structure and function and increase habitat heterogeneity and biodiversity. The extensive influence mammals have on ecosystems results in important services that contribute to human well-being, such as pollination, insect pest control, and bioturbation of soils. The rapid declines in abundance of many mammal populations and the associated increase in extinction risk raise conservation concerns for mammals. To maintain mammalian diversity and the critical ecosystem processes they provide, scientists need to mobilize concern for their status and strive for more effective and comprehensive conservation action. We provide insights and synthesis on the ecological role of mammals and highlight key research questions and future directions for their conservation.
Aim: Every spring endangered Mexican long-nosed bats (Leptonycteris nivalis) migrate up to 1200 km from central Mexico to southern United States. Evidence suggests that L. nivalis follows the blooms ...of paniculate agave plants (genus Agave, subgenus Agave). Paniculate agave inflorescences are adapted to attract bats, and studies have indicated that Leptonycteris spp. played a key role in Agave speciation. We test the hypothesis of the Agave migratory corridor by (1) modelling the distribution of the relevant Agave species; and (2) testing whether bat records are significantly related to Agave species richness as predicted by our models. Location: Mexico and United States. Methods: We selected nine paniculate Agave species based on a set of criteria and modelled the current distribution of those species using MAXENT and the Genetic Algorithm for Rule-set Production (GARP), and geographic information systems to analyse the spatial correspondence of Agave richness and presence of L. nivalis. Results: We combined the Agave presence maps that resulted from the models with higher performance to create a richness map. This map indicated up to five species overlapping. L. nivalis occurrence areas correspond with areas with two, three and four Agave species more often than random expectations at the 0.05 significance level. The opposite is observed for areas with 0 Agave species where L. nivalis correspond less often than random. Main conclusions: Presence-pseudo-absence and presence-background modelling tools allowed us to map potential Agave presence. These maps could guide conservation actions to ensure the maintenance of this pollination corridor. Areas with higher number of Agave species are distributed along mountain chains and may provide foraging resources for L. nivalis for longer period of time during its migration. We recommend implementing a long-term monitoring programme in those areas to document inflorescence timing in Agave species and the presence of L. nivalis.
Environmental pollutants produce adverse effects on organisms and ecosystems. Biomonitoring and biomarkers offer a reasonable approach to make these assessments. Induced genetic changes can be using ...as a biomarker in organisms that react to a given compound in the ecosystem. Monitoring environmental genotoxicity necessitates the choice of model animals known as “sentinels or biological monitors” and the suitability of validated tests for DNA damage evaluation. We aimed to estimate the DNA damage produced by thermal stress in the leukocytes of the Mexican free-tailed bat (
Tadarida brasiliensis
). The DNA damage in bat leukocytes exposed to different temperatures (35 °C, 45 °C, and 55 °C) was evaluated by the adapted chromatin dispersion test (CDT) and the results were confirmed by the alkaline comet test. The CDT permitted a clear representation of leukocytes with fragmented DNA and of nonfragmented DNA. In addition, we detected nuclear anomalies in relation to cell death cellular swelling, nuclear fragmentation, and chromatin lysis. The alkaline comet assay revealed that the halos of diffuse chromatin include fragmented DNA. The assay of the method employing the CDT is well established, precise, and cost-effective for the routine quantitative analysis of DNA damage on the effect of the leukocytes of bats exposed to thermal stress. This could also apply as a sensitive screening tool for the evaluation of genotoxicity in environmental protection programs.
One of the key drivers of pollinator declines is land cover change. We documented for the first time the impacts of over three decades of land cover change in Mexico on the plant resources of an ...endangered migratory pollinator, the Mexican long-nosed bat, Leptonycteris nivalis. This species is considered endangered under national and international criteria due to population declines over 50% in the past 10 years. Pregnant females of this bat species migrate every year following the blooms of Agave spp. from central Mexico to the southern United States; moving pollen over its 1,200 km long migratory corridor and pollinating distant populations of Agave spp. Increases in human populations density and agricultural expansion may be reducing agave habitat over time. The objective of our study is to understand the land cover change trends in the northern range of the bat and identify potential fragmentation patterns in the region. We analyzed changes that occurred in three vegetation types where agaves are found in five time periods 1985, 1993, 2002, 2007 and 2011. The area of the three vegetation types selected was reduced by using only the overlap with potential agave habitat created with ecological niche modeling algorithms to obtain the available agave habitat. We then calculated fragmentation metrics for each period. We found a significant portion of habitat lost mainly due to expansion in agriculture. The total number of patches increased after 1985. Only 9% of the available agave habitat in 2011 is inside the limits of protected areas. We recommend restoring agave populations in depleted areas to help prevent soil erosion and provide multiple socio-economic benefits for the region in the short term, and, in the long-term maintaining foraging resources for nectar-feeding bats.
Most bats depend strongly on surface water to survive and reproduce, and thus it is a limiting resource in markedly seasonal environments, such as semiarid and temperate Mexico. Cattle ranching, an ...important activity in these areas has resulted in construction of rainwater reservoirs that may represent the only available surface water during the dry season. Using acoustic detectors we measured activity in cattle ponds at La Michilía Biosphere Reserve, Durango, Mexico to assess patterns of use by insectivorous bats. We tested for differences in activity between ponds and seasons, and for relationships between bat activity and a set of environmental and pond variables. Bat activity was significantly higher at ponds in the dry season; ponds were used by aerial, trawling, and gleaning insectivores. In the rainy season gleaners did not use ponds, and the other guilds used them less frequently. Larger, older ponds with aquatic vegetation were used more frequently in the dry season, whereas maximum temperature and moon phase affected use in the rainy season. Cattle ponds are common in rangelands and forests of northern Mexico; they constitute important foraging and drinking resources in an area that harbors the largest populations of insectivorous bats in the world.
Abstract
Aim
Every spring endangered Mexican long‐nosed bats (
L
eptonycteris nivalis
) migrate up to 1200 km from central Mexico to southern United States. Evidence suggests that
L. nivalis
follows ...the blooms of paniculate agave plants (genus
Agave
, subgenus
Agave
). Paniculate agave inflorescences are adapted to attract bats, and studies have indicated that
Leptonycteris
spp. played a key role in
Agave
speciation. We test the hypothesis of the
Agave
migratory corridor by (1) modelling the distribution of the relevant
Agave
species; and (2) testing whether bat records are significantly related to
Agave
species richness as predicted by our models.
Location
Mexico and United States.
Methods
We selected nine paniculate
Agave
species based on a set of criteria and modelled the current distribution of those species using
maxent
and the Genetic Algorithm for Rule‐set Production (GARP), and geographic information systems to analyse the spatial correspondence of
Agave
richness and presence of
L. nivalis
.
Results
We combined the
Agave
presence maps that resulted from the models with higher performance to create a richness map. This map indicated up to five species overlapping.
L. nivalis
occurrence areas correspond with areas with two, three and four
Agave
species more often than random expectations at the 0.05 significance level. The opposite is observed for areas with 0
Agave
species where
L. nivalis
correspond less often than random.
Main conclusions
Presence–pseudo‐absence and presence–background modelling tools allowed us to map potential
Agave
presence. These maps could guide conservation actions to ensure the maintenance of this pollination corridor. Areas with higher number of
Agave
species are distributed along mountain chains and may provide foraging resources for
L. nivalis
for longer period of time during its migration. We recommend implementing a long‐term monitoring programme in those areas to document inflorescence timing in
Agave
species and the presence of
L. nivalis
.
INTRODUCCIÓN:
Los murciélagos nectarívoros cavernícolas enfrentan mayor riesgo de extinción comparado con otros murciélagos debido a sus hábitos alimenticios restringidos y la limitada disponibilidad ...de cuevas con las características requeridas por estas especies. Literatura reciente de biología de la conservación sugiere que las estrategias de conservación exitosas deben incluir fundamentos biológicos y sociales. Este artículo presenta las perspectivas biológicas y sociales consideradas para implementar esfuerzos de conservación de las especies amenazadas Leptonycteris nivalis y Choeronycteris mexicana en los estados de Coahuila y Nuevo León. Nuestros objetivos fueron: 1) documentar las cuevas usadas por estas especies, 2) describir estrategias de conservación basadas en la comunidad que vinculan a actores clave (comunidades locales, científicos, educadores, organizaciones no gubernamentales, entidades gubernamentales) resultando en una red de conservación, y 3) proponer estrategias para reforzar los vínculos entre los actores clave de la red de conservación de murciélagos de manera que se mantenga a largo plazo.
MÉTODOS:
Para documentar cuevas usadas por L. nivalis y C. mexicana en Coahuila y Nuevo León, combinamos la búsqueda de sitios conocidos como refugios en literatura disponible, y muestreos de campo para documentar sitios de refugio no reportados previo a este artículo. Implementamos las estrategias sociales con comunidades locales objetivo por medio de talleres y aplicamos encuestas para obtener indicadores del conocimiento y percepción de los murciélagos por parte de los miembros de las comunidades.
RESULTADOS:
Reportamos seis cuevas refugios de las especies nectarívoras y que en conjunto albergan un total de 12 especies de murciélagos (<xref ref-type="table" rid="t1">Tabla 1 ). Las estrategias de conservación basadas en la comunidad que implementamos se describen en cuatro fases: información, comunicación, educación, y capacitación. Participaron 574 residentes de 52 comunidades en la zona de estudio. Las encuestas indican que el 60 % de los participantes no tienen conocimiento de la biología de los murciélagos, el 80 % desconoce sus funciones ecológicas, y el 71 % menciona que son animales que generan miedo.
CONCLUSIONES:
Proponemos una red de conservación conformada por actores clave (comunidades locales, científicas, organizaciones no gubernamentales, entidades gubernamentales, e instituciones financiadoras) en donde los vínculos se refuerzan por medio de una comunicación bidireccional (<xref ref-type="fig" rid="f2">Figura 2 ). El flujo de recursos e información a través de redes como la aquí propuesta facilita la integración de perspectivas sociales y biológicas esenciales para lograr acciones de conservación exitosas.
Societal Impact Statement
Crop wild relatives (CWR) are plant taxa closely related to crops and are a source of high genetic diversity that can help adapt crops to the impacts of global change, ...particularly to meet increasing consumer demand in the face of the climate crisis. CWR provide vital ecosystem services and are increasingly important for food and nutrition security and sustainable and resilient agriculture. They therefore are of major biological, social, cultural and economic importance. Assessing the extinction risk of CWR is essential to prioritise in situ and ex situ conservation strategies in Mesoamerica to guarantee the long‐term survival and availability of these resources for present and future generations worldwide.
Summary
Ensuring food security is one of the world's most critical issues as agricultural systems are already being impacted by global change. Crop wild relatives (CWR)—wild plants related to crops—possess genetic variability that can help adapt agriculture to a changing environment and sustainably increase crop yields to meet the food security challenge.
Here we report the results of an extinction risk assessment of 224 wild relatives of some of the world's most important crops (i.e. chilli pepper, maize, common bean, avocado, cotton, potato, squash, vanilla and husk tomato) in Mesoamerica—an area of global significance as a centre of crop origin, domestication and of high CWR diversity.
We show that 35% of the selected CWR taxa are threatened with extinction according to The International Union for Conservation of Nature (IUCN) Red List demonstrates that these valuable genetic resources are under high anthropogenic threat. The dominant threat processes are land use change for agriculture and farming, invasive and other problematic species (e.g. pests, genetically modified organisms) and use of biological resources, including overcollection and logging. The most significant drivers of extinction relate to smallholder agriculture—given its high incidence and ongoing shifts from traditional agriculture to modern practices (e.g. use of herbicides)—smallholder ranching and housing and urban development and introduced genetic material.
There is an urgent need to increase knowledge and research around different aspects of CWR. Policies that support in situ and ex situ conservation of CWR and promote sustainable agriculture are pivotal to secure these resources for the benefit of current and future generations.
Crop wild relatives (CWR) are plant taxa closely related to crops and are a source of high genetic diversity that can help adapt crops to the impacts of global change, particularly to meet increasing consumer demand in the face of the climate crisis. CWR provide vital ecosystem services and are increasingly important for food and nutrition security, and sustainable and resilient agriculture. They therefore are of major biological, social, cultural and economic importance. Assessing the extinction risk of CWR is essential to prioritise in situ and ex situ conservation strategies in Mesoamerica to guarantee the long‐term survival and availability of these resources for present and future generations worldwide.
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